There are various applications in which a circumferential application of materials to an interior surface of a pipe is preferred. For example, circumferential welding of overlay materials to an interior surface of a pipe is preferred, as fluids tend to flow along longitudinal welds and accelerate wear. It is relatively easy to circumferentially weld a section of straight pipe. When the section of pipe is curved, positioning a circumferential weld along the interior surface of the pipe becomes extremely difficult.
At the present time there is no cost effective method for positioning a circumferential weld along the interior surface of a curved section of pipe. Welds are, therefore, positioned longitudinally. In addition to accelerated wear, fit problems have been encountered due to differences in shrinkage between straight sections of pipe welded circumferentially and curved sections of pipe welded longitudinally.